Fluid actuable multi-point microprobe for semiconductors



Oct. 8, 196 8 E. KATTNER ET AL 3,405,361

FLUID ACTUABLE MULTI-POINT MICROPROBE FOR SEMICONDUCTORS Filed Jan. 8,1964 3 Sheets-Sheet 1 72, 7/ r7 a (9} M I l INVENTORS Lionel E. Kattner1 Albert P. Youmans Patrick J. Shasby Attorneys Oct. 8, 1968 KATTNER ETAL 3,405,361

FLUID ACTUABLE MULTI-POINT MICROPROBE FOR SEMICONDUCTORS 5 Sheets-Sheet2 Filed Jan. 8, 1964 INVENTORS s wmmw M 8 D Alm wr $31 KY m "'0 at n 8."mm 0 LAP Oct. 8, 1968 L. E. KATTNER ET AL 3,405,361

FLUID ACTUABLE MULTI-POINT MICROPROBE FOR SEMICONDUCTORS Filed m. a,1964 s Sheets-Sheet 5 INVENTORS Lionel E. Kaftner Albert R YoumansPatrick J. Shasby Jflb 24543 Attorneys United States Patent 3,405,351FLUID ACTUABLE MULTI-POINT MICROPRGBE FOR SEMICQNDUETORS Lionel E.Kattner, Santa Clara, Albert P. Yonmans, Cupertino, and Patrick J.Shasby, San Jose, Calif, assignors to Signetics Corporation, Sunnyvaie,Calif, a corporation of California Filed Jan. 8, 1964, Ser. No. 336,489Claims. (Cl. 324-158) ABSTRACT OF THE DISCLOSURE Multi-point probe forcontacting closely spaced pads of a semiconductor device having aflexible sheet-like member which carries the probes that make contactwith the semiconductor device. The flexible sheet-like member forms partof a chamber, into which a fluid is introduced to deform said member tocause the probes thereon to make contact with the semiconductor device.

This invention relates to a multi-point microprobe, and moreparticularly to a multi-point microprobe for making multiple electricalcontacts with many closely spaced regions on a device as, for example,an integrated circuit or a thin film circuit.

In the development and manufacture of devices utilizing integratedcircuits or thin film circuits, it has been necessary to make contactwith closely spaced regions of the circuits to check the circuits.Heretofore, it has been the practice to use fine wire probes that arepositioned in an appropriate array and spring-loaded in some manner toprovide a pressure connection when brought into contact with the device.The use of such means has been found to have several disadvantages: Theleads are flexible and can be bent out of alignment with their contactareas. It is extremely difficult to construct an array of wires when thearray has a minute geometry due to the difiiculty involved in machininga suitable assembly for supporting the wires. It is difficult tomaintain a uniform spring-loading on all of the leads for the samereasons. Also, it is difiicult to align such an array over the areas itis desired to contact because vision is obstructed by the wiresthemselves. It, therefore, can be seen that there is a need for a newand improved apparatus for overcoming these difficulties.

In general, it is an object of the present invention to provide amulti-point microprobe which overcomes the above named disadvantages.

Another object of the invention is to provide a micro probe of the abovecharacter in which it is possible to precisely position the microprobeand to readily view the areas being contacted by the microprobe.

Another object of the invention is to provide a microprobe of the abovecharacter in which the probes can be readily moved into engagement withthe areas to be contacted.

Another object of the invention is to provide a microprobe of the abovecharacter in which the probes are accessible so that electrical contactcan be readily made with the probes.

Another object of the invention is to provide a microprobe of the abovecharacter which can be readily aligned with the device to which contactis to be made.

Another object of the invention is to provide a microprobe of the abovecharacter which can be operated by relatively unskilled personnel.

Another object of the invention is to provide a microprobe of the abovecharacter which can be simply and easily constructed.

Additional features and objects of the invention will 3,405,361 PatentedOct. 8, 1968 appear from the following description in which thepreferred embodiment is set forth in detail in conjunction with thefollowing drawings.

Referring to the drawings:

FIGURE 1 is a side elevational view, partly in crosssection, of amulti-point microprobe incorporating our invention.

FIGURE 2 is a partial side elevational view of the microprobe shown inFIGURE 1.

FIGURE 3 is a cross-sectional view taken along the line 3-3 of FIGURE 1.

FIGURE 4 is a partial front elevational view of the microprobe as shownin FIGURE 1.

FIGURE 5 is an exploded isometric view of a portion of the microprobe.

FIGURE 6 is a plan view of one of the elements showing the thin filmcircuitry utilized.

FIGURE 7 is an enlarged cross-sectional view of a portion of themulti-point microprobe.

FIGURE 8 is a cross-sectional view looking along the line 8-8 of FIGURE7.

In general, our microprobe which is utilized for mak ing contact withclosely spaced areas on a device consists of a backing plate. Adeformable member which has a relatively flat exposed surface is mountedon the backing plate. At least one probe is mounted on one portion ofthe deformable member and circuitry is connected to the probe. Means isprovided for mounting the backing plate and the device to permitrelative movement between the same so that the probe or probes carriedby the deformable member are in relatively close proximity to thedevice. Means is also provided for causing the portion of saiddeformable member carrying the probe to be deformed from its normalcondition to move the probe or probes into contact with said device.

More particularly as shown in the drawings, our multipoint microprobeconsists of a stand '11. A microscope 12 is mounted on the stand. Themicroprobe also consists of a probe assembly 13 and a device holder orWorktable 14. Means 16 is provided on the stand for causing relativemovement between the probe assembly and the device holder. A markingdevice 17 is mounted on the stand for marking defective devices.

The stand 11 consists of a base 21. A support block 22 is mounted on thebase. A vertically extending support column 23 is secured to the blockby suitable means such as cap screws 24. The microscope 12 is mountedupon the upper end of the vertical support column 23 and is of aconventional type. It includes eyepieces 26, a lens system 27 of a fixedmagnification and a knob 28 for adjusting the focus of the microscope.

The means 16 for causing relative movement between the probe assemblyand the device holder consists of a vertically movable stage 31 and ahorizontally movable stage 32 which is mounted on the vertically movablestage 31. The vertically movable stage 31 consists of a horizontal plate34 which is afiixed to the upper end of a block 36. The block 36 isslidably mounted for vertical movement on a block 37 which carries means(not shown) controlled by vernier kobs 38 for causing relatively fineadjustable movement of the block 36 relative to the block 37. The block37 is mounted for vertical sliding movement with respect to the block 22and means (not shown) controlled by knobs 39 is provided for a coarseand relatively rapid vertical adjustment of the plate 34.

The horizontally movable stage 32 consists of a mounting plate 41 whichis mounted for pivotal or rotational movement on the plate 34 bysuitable means. As shown, such means can include a cap screw 42 and awasher 43, and cap screws 45 (FIGURE 4) which engage a portion (notshown) of the plate 41 and serve to frictionally retain the plate 41 inthe desired position relative to the plate 34 after it has been shifted.Means (not shown) is provided which includes two knobs 46 and 47 foradjusting the plate 41 in a horizontal direction, namely, in a lateraldirection and in a back and forth direction. For example, the knob 46can be utilized for moving the plate 41 in a sideways or lateraldirection and the knob 47 can be utilized for moving the plate 41 in aback and forth direction while at the same time rotating it about thevertical axis formed by the screw 42.

It should be pointed out that the stages 31 and 32 are of a conventionalconstruction with the exception of the rotational movement provided, andare often used in conjunction with microscopes.

The device holder or device worktable 14 is mounted upon the plate 41 ofthe horizontally movable stage 32 and consists of a rectangular box 51which is provided with four side walls 52 and a bottom wall 53. Arelative- 1y rigid and porous member 54 formed of a suitable materialsuch as sintered bronze is mounted upon the box and serves to form thetop side of the box so that an enclosed chamber 56 is formed within thebox.

Devices such as semiconductor devices 57 and 58 shown in the drawing areadapted to be positioned upon the box 51. Suitable means is provided forretaining the devices 57 and 58 in a fixed position on the box 51 and,as shown in the drawing, consists of a connector 61 which is mounted onone side wall 52 of the box and opens into the chamber 54. A hose 62 hasone end connected to the connector 61 and has its other end connectedthrough a control valve 63 to a suitable source of vacuum (not shown) sothat the chamber 56 may be placed under a continuous vacuum. When thechamber is under a vacuum or below atmospheric pressure, air is beingdrawn continuously through the member 54 of sintered material to therebysuck the devices 57 and 58 into substantial frictional engagement withthe member 54 to thereby prevent movement of the same relative to thebox 51. It is readily apparent that merely by varying the vacuum in thechamber 56, the force applied to the devices 57 and 58 to hold them inplace on the box 51 can be varied.

The probe assembly 13 consists of a mounting plate 66 which is securedto a mounting block 67. The mounting block 67 is secured to the block 22by suitable means such as two side plates 70 and cap screws 71, as shownin FIGURE 2.

The mounting plate 66 is provided with a rounded outer end which isprovided with a circular opening 74. The front mounting plate is alsoprovided with a circular recess 76 which is of a slightly largerdiameter than the opening 74 and which is in alignment with the opening74 but opening from the bottom side of the mounting plate 66. A disc 77of a suitable transparent material such as plastic is mounted in therecess 76. A backing plate 78 having the same general shape as the frontend of mounting plate 66 and formed of a suitable material such astransparent plastic is positioned below the front mounting plate. Thedisc 77 is secured to the backing plate 78 by cap screws 79 positionedin notches 81 provided in the mounting plate and extending through holes82 in the disc 77 and threaded into holes 83 provided in the backingplate 78. An additional cap screw 34 extends through a hole 86 in themounting plate 66 and is threaded into a hole 07 in the backing plate 78to secure the plate 66 to the plate '78.

Suitable sealing means is provided between the backing plate 78 and thedisc 77 and consists of an O-ring 88 which is disposed in an annularrecess 89 formed in the lower surface of the disc 77.

The backing plate 78 is formed with a circular hole 91 which is ingeneral axial alignment with the disc 77. A vertical passage 92 isprovided in the disc 77 and opens into a chamber 93 formed by the hole91. The passageway 92 is connected to a horizontally extending passage-A way 94. A tube 96 is mounted in the disc 77 and has its bore 97opening into the passageway 94. The tube 96 extends through a hole 98provided in the mounting plate 66 and is connected to a hose 99 which isconnected to a suitable source of fluid under pressure as, for example,the exhaust side of a vacuum pump which is utilized for supplying thevacuum to the hose or tube 62.

A deformable member 101 is mounted upon the lower surface of the backingplate '78. The deformable member 101 can be formed of any suitablematerial such as a thin transparent plastic film which is bonded to thebacking plate 78 in a suitable manner such as by heat. This deformablemember 101 extends across the hole 91 so that the portion 101a of thedeformable member extending across the chamber 93 can be deformed ashereinafter described.

A plurality of probes 102 are mounted on the portion 101a of thedeformable member 101 in a desired geometrical configuration. Circuitry103 is provided on the deformable member 101 and is connected to theprobes 102. The probes 102 and the circuitry 103 can be formed in anysuitable manner. For example, as shown in the drawings, the circuitryand probes 103 and 102 can be formed by thin film techniques. As is wellknown to those skilled in the art, the geometry of the metallic film canbe confined to desired areas by conventional masking and etchingtechniques to provide any desired pattern. Thus, as shown particularlyin FIGURE 6, the circuitry 103 consists of a plurality of relativelynarrow leads 104 which are formed as a thin film on the deformablemember.101 and which extend from a rear edge 78a of the backing plate 78where they form large, very accessible contact areas or terminalportions 194:]. As hereinafter explained, the terminal portions 104a ofthe leads adjacent the edges 78a serve as connecting terminals which areremovably positioned in a connector block 106 secured to the mountingplate 66 by suitable means such as cap screws 107.

The leads 10 1 extend forward and are gradually tapered as shown andterminate in the portion 101a of the deformable member 101. The ends ofthe leads are provided with raised portions which form the probes 102 asshown particularly in FIGURE 7. These raised portions can also be formedby conventional thin film or plating techniques. It is readily apparentthat the positioning of the probes on the portion 101a can be in anydesired pattern as, for example, the substantially circular patternshown in FIG- URE 6.

With the construction hereinbefore described, it can be seen that thebacking plate 78 which carries the thin film circuitry and probes 102can be readily removed from the connector 106 merely by removing thescrews 79 and 84 that a replacement backing plate can be readilyinserted.

The marking device 17 consists of an arm 111 which is secured to avertical shaft 112 by suitable means such as a cap screw 113 which isthreaded into the arm 111 and causes the arm to frictionally engage theshaft 112. The shaft 112 is rotatably mounted in a bearing 116 which ismounted in the mounting block 67. A cap screw 117 and a washer 110 areprovided for retaining the shaft 112 in the bearing 116.

A spring-loaded plunger 121 is mounted on the outer end of the arm 111.The spring-loaded plunger is mounted in a cylindrical member 122 whichis carried by a mounting member 123. The cylindrical member 122 isclamped into the mounting member 123 by a cap screw 124. Means isprovided for mounting the member 123 on the outer end of the arm 111 topermit adjustment of the same. This means consists of a recess 126 whichis provided on the outer end of the arm 111 and which is adapted toreceive an extension 1230 provided on the support member 123. Screws127, 128 and 129 are mounted on the outer end of the arm 111 and extendinto the portion 12311 of the support member 123. The screw 128 isprovided with an eccentric (not shown) so that the position of theplunger 121 relative to the arm 111 can be shifted in directionslongitudinally and laterally of the arm 111 merely by loosening of thescrews 128 and turning of the screw 127.

The plunger 121 is adapted to engage an ink pad 131 carried by an inkpad holder 132 mounted on the stage 32.

Means is provided for yieldably urging the arm 111 to an out-of-the-wayposition and consists of a spring 134 which has one end secured to a pin136 provided on the vertical support column 23 and which has the otherend secured to a pin 136 provided on the arm 111.

Means is provided for limiting the travel of the arm 111 between aposition overlying the ink pad 131 on one side of the mounting plate 66and a position overlying the device. This means consists of a bracket141 which is secured to the side plates 70 by suitable means such as capscrews 142. A cap screw 143 is threaded into the outer end of thebracket 142 and is adapted to be engaged by the arm 111 to limit thetravel of the arm under the urging of the spring 134. A lock nut 144 isprovided to retain the cap screw 143 in the desired position. The otherstop means consists of a bracket 146 which is secured to the supportblock 22 by suitable means such as cap screws 147. An upright member 148is secured to the bracket 146 by suitable means such as screws 149. Acap screw 151 is threaded into the upper end of the member 148 and isretained in a predetermined position by a lock nut 152.

Operation and use of our multi-point microprobe may now be brieflydescribed as follows. Let it be assumed that it is desired to check adevice which is commonly known as an integrated circuit ormicrocircuitry such as the devices 57 and 58 shown in FIGURE 5 of thedrawings. Also, let it be assumed that a vacuum is applied to the hose62 so that air is continuously drawn through the member 54 of sinteredmaterial so that the devices 57 and 58 are held down relatively tightlyon the member 54. After this has been accomplished, the knob 39 isadjusted to bring the device into relatively close proximity to theprobes 102. Thereafter, with the use of the microscope 12, the device isprecisely positioned so that the areas of the device to be contacted bythe probes immediately underlie the probes. This is accomplished byadjusting the vernier knob 38 for vertical movement and for adjustingthe knob 46 for lateral movement and the knob 47 for back and forthmovement. This can be readily accomplished because the device to betested can be seen through the microscope through the opening 74 in thefront mounting plate 72, the transparent disc 77 and through thetransparent deformable member 101. Very accurate alignment can beobtained because the probes 102 which are at the extremities of theleads 104 can be exactly aligned with the areas it is desired to contacton the device 57, as can be seen from FIGURE 8. Thereafter, as soon asthe proper alignment has been made, a control valve 100 can be operatedso that a fluid under pressure is applied to the chamber 93 through thebore 97, the passages 94 and 92. As pressure is applied, the relativelythin diaphragm formed by the deformable member 101 will be deformed orbowed outwardly so that the probes 102 are urged into a firm contactwith the closely spaced areas of the semiconductor device to be testedor checked.

It is readily apparent that by varying-the fluid under pressure which isapplied to the chamber 93, the contact pressure which the probes 102make with the device can be varied. Because the probes 102 are raisedabove the surface of the leads 104, the leads 104 will not come incontact with the semiconductor device and, therefore, there is nopossibility of shorting out areas of the semiconductor device. Ifdesired to provide additional insurance, an insulating film in the formof a thin coating of varnish, plastic or other insulating material canbe placed on the leads 104 to prevent any possibility of shorting outany portion of the semiconductor device when the probes 102 are movedinto contact with the semiconductor device.

After the semiconductor device has been checked and found to besatisfactory, the air pressure on the tube 99 can be removed.Thereafter, the vacuum can be removed on the chamber 56. The stages 31and 32 can then be lowered and the device which has been tested can beremoved. Additional devices can then be placed on the stage and checkedin the same manner.

In the event a device is found to be unsatisfactory, the marking devices17 can be utilized to mark the semiconductor device as being defective.This can be accomplished by first pressing the plunger 121 until itengages the ink pad and thereafter swinging the arm to the left until itengages the cap screw 1511. Thereafter, the plunger 121 is depressed sothat it strikes the semiconductor device to mark it with ink to indicatethat it is defective.

Although we have shown an ink marking device for indicating defectivedevices, it is readily apparent that other types of marking devices canbe provided. For example, a small motor driven burnishing wheel or thelike can be provided on the arm 111 for destroying or scribing certainof the elements of the semiconductor device to indicate that it isdefective.

From the foregoing, it can be seen that we have provided a new andimproved multi-point microprobe which is particularly adapted for usewith semiconductor and similar devices which utilize microcircuitry.With the arrangement disclosed, it is possible to precisely position themulti-point probe so that very closely spaced areas of a semiconductordevice can be contacted. In addition, by utilization of the deformablemember, it is possible to ensure that the probes will make good contactwith these areas of the semiconductor device.

We claim:

1. In a microprobe for making contact with closely spaced areas on adevice, a stand, a microscope mounted on the stand, a stage, means formounting said stage on said stand to permit vertical movement, back andforth and sideways movement of the stage, a backing plate, means formounting said backing plate on said stand, said backing plate having ahole therein, a deformable member mounted on said backing plate andextending across said hole, a plurality of probes mounted on a portionof said deformable member extending across said hole, circuitryconnected to said probes, means mounted on the backing plate for forminga chamber overlying the portion of said deformable member extendingacross said hole, means for mounting a device on said stage, and meansfor supplying fluid to said chamber to cause said deformable member tobe deformed from its normal position to thereby urge the probes intocontact with closely spaced areas on said device, said means for forminga chamber and said deformable member being transparent so that thedevice and the probes can be seen when looking through said means forforming a chamber and said deformable member to thereby permit precisepositioning of the device and the probes by use of the microscope.

2. A microprobe as in claim 1 wherein said means for mounting saiddevice on said stage includes means forming a chamber having a porous,relatively flat upper wall and means for withdrawing air from thechamber so that air passes through the porous wall, the porous wallbeing adapted to receive the device.

3. A microprobe as in claim 1 together with an arm pivotally mounted onsaid stand, and a marking device carried by said arm, said arm beingmovable between an out-of-the-way position and a position in which themarking device overlies the device on said stage.

4. A microprobe as in claim 3 together with means for yieldablyretaining said marking device in said out-ofthe-way position, and stopmeans for limiting the travel of said arm in said out-of-the-wayposition, and additional stop means for limiting the travel of said armto the position in which it overlies said device.

5. In a probe assembly for making separate and independent contacts withspaced contact pads arranged in a predetermined pattern adjacent theouter perimeter of a semiconductor device, a relatively rigid backingmember, a planar sheet-like deformable member of insulating materialmounted on the backing member so that said deformable member has anexposed substantially planar exterior surface, a plurality of spacedprobes formed of a thin metallic film adherent to and supported by saidsurface so that they are insulated from each other, said probes havinginner extremities which terminate in contact areas forming a patterncorresponding to the pattern of the contact pads of the device to becontacted, means mounting said backing member and said device to becontacted to permit relative movement between the same, said deformablemember being substantially transparent and at least a portion of saidbacking member being substantially transparent so that the pads of thedevice and the contact areas of the probes can be viewed through thebacking member and the deformable member to facilitate positioning thecontact areas and the contact pads so they face each other, said backingmember and said UNITED STATES PATENTS 3,319,166 5/1967 Coleman 324-1582,954,521 9/1960 McKee 32472.5 3,185,927 5/1965 Margulis 3241583,271,673 9/1966 Woroble 324-725 FOREIGN PATENTS 917,893 2/1963 GreatBritain.

RUDOLPH V. ROLINEC, Primary Examiner. E. L. STOLARUN, AssistantExaminer.

